Disclosed is a tow-bar which is especially suited for towing airplanes, such as single-engine Cessna airplanes. The disclosed quickly foldable compact tow-bar can be unfolded to tow an airplane in an easy and safe manner and folded back to stow away in the luggage compartment of the airplane. Normally, tow-bars are made relatively short so that they can be stowed in the luggage compartment of a small airplane.
Tow-bars for towing vehicles including airplanes are known. U.S. Pat. No. 4,991,862 discloses an aircraft towing apparatus, while U.S. Pat. No. 5,649,679 describes an airplane nosewheel fairing cover to prevent the nosewheel from becoming cracked or scratched as an airplane tow-bar is attached or removed from the nose-wheel strut.
FIG. 1 shows front portion of a single-engine Cessna 10 where a tow-bar 20 has been attached to strut 30 over the nose-wheel fairing 40 covering nose-wheel 50. It will be noted that handle 60 of tow-bar 10 is well under the belly 70 of the airplane and is reachable through and between the blades of propeller 80.
As better seen in FIG. 2, tow-bar 20 comprises a tubing material that has substantially been formed into an irregular U-shape having a first end and a second end. The dosed first end of the U-tube forms handle 60, while the two legs 63 and 65 form the open second end 90. The two open legs are configured to fit over protrusions on the sides of the strut 30 of the airplane shown in FIG. 1. Usually, the openings at the end of the legs 63 and 65 engage lugs (not shown) on strut 30 shown in FIG. 1, also seen at a different angle in FIG. 4.
In operation, the operator of the tow-bar approaches the airplane by holding the tow-bar by the handle 60 while opening the legs 63 and 65 by pushing a lever 67 forward in the direction of opening 90, as shown in FIG. 3.
Lever 67 is attached to one of the legs 63 at a pivot point “a” while being attached to one end of a connector plate 62 at another pivot point “b” as shown in FIGS. 2 and 3. Opposite end of connector plate 62 is attached to the other leg 65 of tow-bar 20 at pivot point “c”.
As lever 67 travels forward in the direction of opening 90, the lever flexes the irregularly U-shaped tubing 20 to open legs 63 and 65 wider 90′ as seen in FIG. 3. As pivot point “b” travels past an axis formed between pivot points “a” and “c”, lever 67 stops against stop 64, as shown in FIG. 3. One of the legs, either 63 or 65 may now be engaged with a corresponding lug (not shown) on strut 30 and the other leg engaged to the other lug by pulling lever 67 from its stop position. With the tow-bar engaged onto the strut 30, airplane 10 is now ready to be towed, as shown in FIG. 4.
As is shown in FIG. 4, the body force applied to manual towing of airplanes with tow-bars that do not extend beyond the propeller may cause difficulty in moving an airplane which may weigh more than 3000 pounds. This is because, a normal human operator 100 needs to bend forward to reach for the handle 60, usually with one hand 103, while seeking support somewhere else, usually the nearest propeller cone 15, with the other hand 105, as depicted in FIG. 4, thus making it difficult to exert full towing force due to the awkward position of the body of the operator 100. In addition, there is always the hazard of being caught (as has been reported in the past) in between the blades of an unintentionally engaged propeller due to some malfunction of some component in the airplane.
Two-piece and longer tow-bars are also known. However, they need to be assembled and disassembled in each use. Furthermore, even after disassembly, they are not configured to fit in the rear portion of a luggage compartment of a single-engine airplane, such as in Cessnas'. What is needed is an ergonomically sound, compact tow-bar which can be extended, and yet folded and stowed away quickly.